Employee Benefit Plans (Details 3) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Amounts in accumulated other comprehensive loss that are expected to be recognized as components of net periodic benefit cost
Prior service cost	$ (543)
Net actuarial loss	3,006
Pension Benefits
Amounts in accumulated other comprehensive loss that are expected to be recognized as components of net periodic benefit cost
Prior service cost	0
Net actuarial loss	1,569
Postretirement Benefits
Amounts in accumulated other comprehensive loss that are expected to be recognized as components of net periodic benefit cost
Prior service cost	(543)
Net actuarial loss	$ 1,437